It is conventional in the melting of iron and in the refining of iron into steel to employ fluxing agents for conditioning the molten slag layer to promote the extraction of impurities from the molten metal bath and to further provide reactive substances for combining with impurities such as sulfur and phosphorus which migrate to and can be effectively extracted with the resultant slag layer. The basic flux employed in iron and steel-making operations is lime or limestone, and particularly, "burnt lime" (CaO), which is effective to condition the molten slag upon dissolution therein. It has also been conventional in accordance with prior art practices to employ lesser amounts of fluorspar (CaF.sub.2) as a supplemental slag conditioner and fluxing agent for increasing the fluidity of the slag and to further enhance the rate of dissolution of the lime and its chemical reactivity with the impurities present. The relatively high cost of fluorspar, the toxic and corrosive nature of fume emission in addition to its action on waste water, requiring neutralization, has prompted a continuing search for substitute materials which effectively reduce or eliminate the use of fluorspar without any sacrifice in the slag fluidizing and conditioning characteristics.
Various materials have heretofore been suggested or proposed for use as a partial or complete substitute for fluorspar, of which the composition as described in U.S. Pat. No. 3,799,762 is typical. Of the various prior art slag conditioning agents heretofore proposed, neither have received widespread commercial acceptance either because of their reduced effectiveness and/or their relatively high cost and/or the difficulty associated in their handling and control of the chemistry of the molten bath.
In accordance with the present discovery, a slag conditioning and fluidizing agent is provided which is of comparable effectiveness to fluorspar, which is substantially more economical, which generates less toxic and corrosive fumes, which requries less waste water treatment and which employs constituents which are in plentiful supply.